This invention relates to exercising devices and, more specifically, to a device primarily directed to the human torso and exercise of the abdominal and lumbar (extensor) paraspinal muscles of the lower back.
The concept of resistance for exercising individual muscles or muscle groups is generally known. Various techniques, such as "sit ups", abdominal "crunches", "push-ups" and "pull-ups" utilize the weight or resistance of the body itself to provide such benefit. Free weights, in the form of barbells and dumbbells have long used for such purposes. Likewise, various weight training or resistance devices have been developed for such purposes. U.S. Pat. No. 4,372,553, to Hatfield, discloses a weightlifting device and method of exercise utilizing a shoulder harness, seat, and weight pulley attachment, to utilize the abdominal muscles in moving a designated weight in a vertical direction. U.S. Pat. No. 4,582,319, issued to Luna, discloses a sit-up exercise bench which utilizes a shoulder harness, bench, and spring resistance in which the user performs sit-up-like exercises but with a greater degree of resistance. U.S. Pat. No. 5,141,482, issued to Hern, discloses an exercising device for utilization with a straightback seat utilizing a shoulder harness and pair of adjustable length shoulder straps which inhibit downward motion when the exerciser moves forwardly against the tension of the cords and tightens the stomach muscles when performing such an exercise. U.S. Pat. No. 5,094,450, issued to Stearns, discloses an abdominal exercise machine in which pressure is applied through the user's chest to a chest pad with resistance provided by a viscous fluid resistance cylinder, or by stacked weights. U.S. Pat. No. 1,969,901 discloses an exercise chair with resistance in the chair provided by a spring mechanism. U.S. Pat. No. 1,973,945, issued to M. I. Chavin et al discloses a combination exercising and massaging apparatus with resistance therein provided by various spring mechanisms. U.S. Pat. No. 5,135,445, issued to Christensen et al, discloses an exercising device for the neck which may be mounted on a standard door and provides resistance through a suspended generally U-shaped leaf spring member.
Further, clinical medical studies have demonstrated the effectiveness of mechanically-aided exercise in situations where the pelvis is fixed in a position which allows the person's back or spine to be exercised both in flexion and in extension. Devices for such purposes, include lumbar extension machines and torso rotation machines, both by MedX Corporation of Ocala, Fla. Such machines are extremely complex. While very effective, their complexity, size and expense does not render them ready susceptible to individual purchase and use, or for portable applications.
While all of the referenced prior art relates, in some respect, to exercise of certain muscle groups by providing a means of resistance to movement through a certain range of motion, such inventions are directed primarily toward one particular muscle group and are further directed to resistance to either a pushing type of muscle motion as in the Christensen, et al patent, or a pulling resistance mechanism which seems to have found particular favor in devices relating to abdominal muscle groups such as demonstrated in the patents issued to Luna, Hatfield and Hern.
While all of the referenced prior art relates, in some manner, to exercise or therapy of particular muscles or muscle groups, for the most part, such devices are extremely limited in that their application is generally limited to one particular muscle group, or they are directed to devices which are inordinately complicated and, often, extremely expensive. The referenced prior art is not directed to a simplistic, portable device which may be interchangeably used to exercise the abdominal and lower back muscle groups of the human torso.
Exercise of these muscle groups has become particularly important in the rehabilitation of back injuries and in physical therapy designed to promote recovery and to prevent recurrence. Machines typically utilized for these purposes are, for the most part, extremely expensive and usually available only in rehabilitation centers, medical facilities and health clubs. The expense of such machines does not often render them economically feasible for individual use outside of those settings. Even if such machines are within the economic reach of a person in need, they are typically large, heavy and cumbersome, and not easily or economically transportable for use when traveling, or otherwise away from home for any period of time.
The concept of a resilient member for providing resistance is also known. Although the above-disclosed prior art does not make mention of it, the utilization of molding or laminated fiberglass "limbs" as components of bows is well known in the archery industry. U.S. Pat. No. 3,993,039, issued to Groves et al, discloses a compound archer bow utilizing flexibly resistent bow limbs. U.S. Pat. No. 4,201,177, issued to Holman et al, likewise discloses a compound bow utilizing the opposite flexible limbs. Another example of such prior art is U.S. Pat. No. 4,593,674, issued to Kudlacek, which specifically references flexure of opposing limbs of the bows structure. Although no one in the archery industry, however, none of the referenced prior art relative to exercising devices incorporates the limb structure expressly referenced in the archery-related patents.
Accordingly, a need exists for an exercising device capable of providing resistance training for the lower back and abdominal muscle groups of the human torso, which device is portable, easily assembled and operated by one person and relatively inexpensive to purchase and maintain. Specifically, what is needed is a device which may be used interchangeably to exercise both the lower back and abdominal muscles, which is lightweight, easily disassembled and easily carried, and which provides a minimum of moving parts for safety considerations and ease of maintenance.